COLORLESS, TRANSPARENT AND HEAT RESISTANT POLYURETHANE FILMS AND METHODS FOR MANUFACTURING THE SAME

Abstract

The present inventions concerns compositions for producing thermoset polyurethanes, comprising polyisocyanates and polyols selected from a list consisting of allieyclic, aromatic compounds and branched polyesters. The films obtained from these compositions exhibit a high transparency, high thermal stability and good chemical resistance, and a method to produce the same. The said polyurethane films can be widely used in electronics industry where high transparency, high thermal resistance and good chemical resistance are the main requirements. Particularly, these films can be used as the substrates for conductive coatings and barrier coatings. These functionally coated films are particularly useful in applications such as touch panels or photo-voltaic cells.

Claims

1.-14. (canceled)

15. A polyurethane film, obtained from a composition, comprising polyisocyanates and polyols selected from the group consisting of alicyclic, aromatic compounds and branched polyesters.

16. The polyurethane film according to claim 15, wherein the polyols are diols, triols or tetraols, preferably diols and/or triols selected from the list consisting of the following compounds (a) to (l) (a) ##STR00012## (b) ##STR00013## (c) ##STR00014## (d) ##STR00015## (e) ##STR00016## (f) ##STR00017## (g) ##STR00018## (h) ##STR00019## (i) ##STR00020## (j) ##STR00021## (k) ##STR00022## (l) a branched polyester polyol.

17. The polyurethane film according to claim 15, wherein the polyisocyanate is selected from tetramethylene diisocyanate, hexamethylene diisocyanate, 2-methylpentamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, dodecanemethylene diisocyanate, 1,4-diisocyanatocyclohexane, 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate, 4,4′-diisocyanatodicyclohexylmethane, 4,4′-diisocyanato-3,3′-dimethyldicyclohexylmethane, 4,4′-diisocyanato-2,2-dicyclohexylpropane and their trimers, urethanes, biurets, allophanates or uretdiones.

18. The polyurethane film according to claim 15, wherein the polyisocyanate is isophorondiisocyanate, preferably a trimer of isophorondiisocyanate.

19. The polyurethane film according to claim 16, wherein the polyisocyanate is a trimer of isophorondiisocyanate and the diol and/or triol is one of compounds (c), (d), (f), (g), (j) and (k).

20. The polyurethane film according to claim 15, having a glass transition temperature Tg according to ASTM D3418 of at least 150° C.

21. The polyurethane film according to claim 15, wherein Tg according to ASTM D3418 is at least 170° C.

22. The polyurethane film according to claim 15, wherein the film is obtained by casting said composition onto a carrier substrate

23. A transparent conductive film, comprising the polyurethane film according to claim 15 as a substrate and a transparent conductive oxide layer on said substrate.

24. The transparent conductive film according to claim 23, wherein the transparent conductive oxide is selected from the group consisting of indium tin oxide, fluorine doped tin oxide, doped zinc oxide such as aluminium-doped zinc oxide, indium-doped cadmium oxide and antimony tin oxide.

25. The transparent conductive film according to claim 23, wherein the transparent conductive oxide layer is deposited by sputtering, metal organic chemical vapor deposition, metal organic molecular beam deposition, spray pyrolysis and pulsed laser deposition.

26. An electronic device, comprising at least one polyurethane film according to claim 15 and/or at least one transparent conductive film according to claim 23.

27. The electronic device according to claim 26, wherein the device is a display, an instrument panel, or a photo-voltaic cell.

28. A method comprising utilizing the films according to claim 15 as substrates for conductive coatings and barrier coatings or as protective films for polarizers in a display.

Description

EXAMPLES

[0035] Components:

[0036] Desmodur® Z4400 (Bayer MaterialScience AG, Leverkusen, Germany), solvent-free, aliphatic polyisocyanate with isocyanurate units based on isophorondiisocyanat, equivalent weight 252 g/Mol.

[0037] Desmodur® VP LS 2249/1 (Bayer MaterialScience AG, Leverkusen, Germany), is a solvent-free, branched short-chain, low viscosity polyester polyol.

[0038] Desmophen® XP 2488 (Bayer MaterialScience AG, Leverkusen, Germany), is a solvent-free, branched polyester polyol.

[0039] Measurements:

[0040] 1. Glass Transition Temperatures (tg)

[0041] The glass transition temperatures (Tg) of the polyurethanes synthesized were measured according to ASTM D3418 using a Differential Scanning calorimeter (DSC) under nitrogen purge with a heating rate of 10° C./min. The temperature range was from 30 to 300° C. The samples were cooled from 300° C. to 30° C. at a cooling rate of 10° C./min. The transition temperature from the second heating was recorded as the glass transition temperature of the sample.

Example 1

[0042] A mixture of 6.72 g of Desmodur® Z4400 from Bayer MaterialScience AG, 3.28 g of bis(2-hydroxyethyl) terephthalate and 10 g of solvent (acetone, methyl ethyl ketone (MEK) or (MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted pre-product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 170° C.

Example 2

[0043] A mixture of 7.24 g of Desmodur® Z4400 from Bayer MaterialScience AG, 2.76 g of hydroquinone bis(2-hydroxyethyl) ether and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 167° C.

Example 3

[0044] A mixture of 6.06 g of Desmodur® Z4400 from Bayer MaterialScience AG, 3.94 g of bis(4-(2-hydroxyethoxy phenyl)sulfone) and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane Obtained shows a glass transition temperature of 189° C.

Example 4

[0045] A mixture of 7.90 g of Desmodur® Z4400 from Bayer MaterialScience AG, 2.10 g of 1,4-benzene dimethanol and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 205° C.

Example 5

[0046] A mixture of 6.22 g of Desmodur® Z4400 from Bayer MaterialScience AG, 3.78 g of 2,2′-isopropylidene bis(p-phenyleneoxy) diethanol and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 166° C.

Example 6

[0047] A mixture of 7.49 g of Desmodur® Z4400 from Bayer MaterialScience AG, 2.51 g of tris(2-hydroxyethyl) isocyanurate and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 223° C.

Example 7

[0048] A mixture of 5.42 g of Desmodur® Z4400 from Bayer MaterialScience AG, 4.58 g of 4,4′-(9-fluorenylidene) bis(2-phenoxyethanol) and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%, The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C for 30 min, 120° C. for 30 min and 150° C. for 60 min. The thermoset polyurethane obtained shows a glass transition temperature of 203° C.

Example 8

[0049] A mixture of 7.83 g of Desmodur® Z4400 from Bayer MaterialScience AG, 2.17 g of 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is not detectable.

Example 9

[0050] A mixture of 7.28 g of Desmodur® Z4400 from Bayer MaterialScience AG, 2.72 g of 1,4-bis(alpha-ydroxy isopropyl) benzene and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is not detectable.

Example 10

[0051] A mixture of 6.95 g of Desmodur® Z4400 from Bayer MaterialScience AG, 3.05 g of bisphenol-A and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is 220° C.

Example 11

[0052] A mixture of 6.75 g of Desmodur Z14400 from Bayer MaterialScience AG, 3.25 g of bisphenol-S and 10 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted product was a stable, clear liquid having a solid content of ˜50%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 1.50° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is 181.5° C.

Example 12

[0053] A mixture of 19.31 of Desmodur® Z4400 from Bayer MaterialScience AG, 7.68 g of Desmophen® VPLS 2249/1 from Bayer MaterialScience AG and 12 g of solvent (acetone, MEK or MIBK) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is 153.3° C.

Example 13

[0054] A mixture of 17.32 g of Desmodur® Z4400 from Bayer MaterialScience AG, 6.68 g of Desmophen® XP 2488 from Bayer MaterialScience AG and 12 g of solvent (acetone, MEK or MIBKg) was weighted into a four-neck flask with condenser, thermometer and overhead-stirrer and stirred at 60° C. The reaction was continued until the NCO content was lower than 3.5%. The reacted solution was then cast onto a substrate material. The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is 154.6° C.

[0055] The resulting Tg obtained in the above examples are summarized in table 1.

[0056] Comparative example 1: Films similar to those described in previous examples were made out of polycaprolactonetriol and Desmodur® XP2489 (an aliphatic polyisocyanate) in a ratio of 35 to 65.

[0057] The cast solution was subjected to thermal curing at 60° C. for 30 min, 120° C. for 30 min and 150° C. for 60 min. The glass transition temperature of the thermoset polyurethane obtained is 75° C.

TABLE-US-00001 TABLE 1 Glass transition temperatures of polyurethanes derived from Desmodur ® Z4400 with different polyols Polyol Code Name of Polyol T.sub.g, ° C. a Bis(2-hydroxyethyl) terephthalate 170.4 b Hydroquinone bis(2-hydroxyethyl) ether 167.7 c Bis(4-(2-hydroxyethoxy phenyl) sulfone) 189.9 d 1,4-Benzenedimethanol 205.7 e 2,2′-isopropylidene bis(p-phenyleneox) 166.1 diethanol f Tris(2-hydroxyethyl) Isocyanurate 223.1 g 4,4′-(9-fluorenylidene) bis(2-phenoxyethanol) 203.4 h 2,2,4,4-tetramethyl-1,3-cyclobutanediol Not detectable i 1,4-bis(alpha-hydroxy isopropyl) benzene Not detectable j Bisphenol-A 220.0 k Bisphenol-S 181.5 l Desmophen ® VPLS 2249/1 153.3 m Desmophen ® XP 2488 154.6 n Polycaprolactonetriol 75